Herbicidal composition

ABSTRACT

A HERBICIDAL COMPOSITION FOR SELECTIVELY KILLING UNDESIRABLE WEEDS IN PADDY RICE FIELDS COMPRISING S-(2-CHLOROBENZYL)-N,N-DI-ISOPROPYLTHIOCARBAMATE AS AN ACTIVE INGREDIENT.

1 Claim ABSTRACT .OF inso Los unn- A herbicidal composition for-"selectively lcilli'ng tindesirable weeds in pa'ddy' rice fields comprising S-( 2j-chloroben zyl) N,N-di-isopropylthiocarbamate as an active .ingredient.

The P it "i nt en r a e q herb d l c npbi w tions containing S-(Z chIorOb'enZyl)-N,N1di isopropylthio carbamate'as an active ingredient'and a method for con: trolling or killing undesirable Weeds 'in paddyricefields by using the above described S chlorbeniyhthiocarbamate as theactive ingredient. v A

This application is a continuation' ofapplication Ser. No. 868,900, filed t. 23; t969rinowaban oned, anda continuation-'in-part'of o r cope'nding'japplication N9. 651,143, filed luly 5, ,1 '967 ,'now lat. No. "3,582,314.

S-chlorobeniyl-thiocarbamate'"according to the present invention is, active asherbicidal.cornpositionf'and has a' high activity for controlling germination of various weeds in agricultural field and particularly, said compound can prevent wire grass (Eleocharis acicularis Roem. et schult), barnyard grass ('Echinochloacrus-galli P. Beauv) and crabgrass (Digitaria adscendens Henr.), which are main noxious weeds in paddy.

Herbicidal composition applied previously to paddy have involved PCP, NIP (active ingredient: 4-nitro-2',4'- dichlorodiphenyl ether), Prometrynetactive ingredient: 2-methylthio-4,6-bis(isopropylaminoy- S triazine) and other numerous compositions, but most of them have been used for controlling germination of weeds after paddy rice plant is planted. These previous herbicidal compositions are effective for therophyte weeds generated at a relatively early stage after planted 'the rice plant, but have extremely poor" activity or substantially no activity for wire grass of perennialweed: Recently, this wire grass has become'- prohlem as preferential weed in' p'addy, be

cause any herbicidal composition, which has no phytotoxicity to paddy rice plant and can prevent exactly wire grass, has never been discovered.

The reason why, wire grasshas been unusually grown in paddy, is based on the fact that in general, the previous herbicidal compositions are spread 3 to 7 days after the rice plant is planted, while generation of wire grass is about 2 weeks after planted; that'is, wire grass is generated when the activity of the'herbicidal compositions are decreased and further wire grass is perennial, so that it has high resistance against the herbicidal composition.

The most active composition for preventing wire grass has been DBN (active ingredient; 2,6-dichlorobenzonitrile), but" this composition is highlyphytotoxic against paddy rice plant, so that it has probl'em'inpractice;

However, the S-chlorobenzyl-thiocarbamate according to the present inventionis excellent in the activity for preventing wire grass and particularly, when it is used in an original stage of growthfiof wiregrass, wire grass is completely prevented in a'n' amount bf less than 500 g./

3,822,124 Patented July 2, 1974 v 10 ares. Particularly, when surface layer of soil or water man a-cm;- is not damaged. When 800 to 1,000 g./ 10 ares are used, the growth is slightly suppressed temporarily but hereafter is not affected and this compound has substantially no damage.

Then, a method for producing S-chlorobenzyl-thiocar- I; bamate according to the present invention will be explaiued inthe following.

z2-chlor'obenzyl mercaptan is dissolved in an inert solvent'such as toluene or benzene and to the resulting solution is added dropwise a solution of phosgene in an inert solventand the resulting mixture is stirred while cooling and added with a hydrochloride acceptor dropwisefiI'hen, the resulting mixture is added dropwise with diisopropylamine and the mixture is reacted. In order to remove hydrochloride of the hydrochloride acceptor U (amines) after completion of the reaction, the reaction product, is washed with water, dried and concentrated.

Furthermore, the resulting liquid is purified by vacuum distillation.

Srchlorobenzyl-thiocarbamate according to the present invention'is mixed with diluents involving carriers and surfactants to prepare dust, emulsifiable concentrate and wettable powder, which are used directly or after diluted with water as herbicidal compositions.

Furthermore, said carbamate can be prepared into granular composition. Namely, said thiocarbamate is increased in an amount with bentonite, clay, talc, limestone, etc. and added'with a binder, such as, PVA (polyvinyl alcohol) and the resulting mixture is kneaded with water and subjected to an extrusion type of granule forming machine and the formed granules are dried. Alternatively,

said thiocarbamate is dissolved in a proper solvent and the solution is homogeneously adsorbed into granular diatomaceous earth, vermiculite, etc. As the other means, by said thiocarbamate is coated surface of granular limestone uniformly. The granules thus obtained are dispersed tive ingredient through anadjuvant, for example, water,

benzene, kerosene, alcohol, acetone, methylnaphthalene, xylene, etc.

The term surfactants used herein means unionic surfactants, such as, polyoxyethylenealkylaryl ether, polyoxyethylenesorbitane monolaurate, etc.; cationic surfactants, such as, alkyldimethylbenzyl ammonium chloride, alkylpyridinium halide, etc.; anionic surfactants, such as,

. alkylbenzene sulfonates, fatty alcohol sulfates, etc.;

amphoteric surfactants, such as, lauryl amine derivatives,

betaine derivatives, dodecyl diaminoethyl glycine, etc.

The invention will be further explained in detail with reference: to the following-preparation examples? EXAMPLE 1' Wettable powder Twenty five parts by weight of S-(2-chlorobenzyl)- N,N-di-isopropylthiocarbamate, 10 parts by weight of white carbon, 60 parts by weight of diatomaceous earth and. St parts by. weight of wetting agent of a mixture of uipdlyoxyethylenealkylphenol ether; 'polyo'xyethylene- 3 phenylphenol ether and polyoxyethylene carbonate were mixed and milled and the resulting powder was suspended in water, which was sprayed.

EXAMPLE 2 Grandule Five parts by weight of S-(2-chlorobenzyl) N,N-diisopropylthiocarbamate were sprayed on and adsorbed in 95 parts by weight of granular diatomaceous earth, which isopropylthiocarbamate, 30 parts by weight of xylene and 20 parts by weight of an emulsifier of a mixture of polyoxyethylenealkylphenol ether, polyoxyethylenephenylphenol ether and polyoxyethylene carbonate were mixed and dissolved. The resulting solution was diluted with water and then sprayed.

EXAMPLE 4 Granule Five parts by weight of S-(2-chlorobenzyl)-N,N-diisopropylthiocarbamate, parts by weight of PCP sodium salt, 50 parts by weight of bentonite, 27 parts by weight of clay, 1 part by weight of sodium alkylarylsulfonate and 2 parts by weight of sodium ligninsulfonate were mixed and milled and then added with a suitable amount of water and kneaded and the kneaded mixture was subjected to an extrusion type of granule forming machine (open having 1 mm. diameter) to obtain granules, which were dried.

In order to show the activity of the herbicidal compositions of the present invention, Experimental Examples are described as follows:

EXPERIMENTAL EXAMPLE 1 Three groups of 3-leaf stage young paddy rice plant (species: Kinmaze), one group of which has two rice plants, were planted in a pot of 15 cm. diameter. After the rice plant took, 30 barnyard sowed on the surface layer of the soil and the pot was filled with water to a depth of 1 cm. and one day later granular compositions containing 5% active ingredients of the present invention (Example 2) were spread in such amounts that the amounts of active ingredients were 100 g., 250 g. and 500 g. per 10 ares. Two weeks after the treatment, the growth degree of the weed and the phytotoxicity on the paddy rice plants were estimated.

Number 7 0! Barn- Number Phytotoxicity Active Dose, yard grass of broadon paddy ingredient g./10 a. plants lea! weeds rice plant Compound A 500 0 0 No damage.

Do 250 1 1 D0. Do -100 2 3 Do. Comlpound B. 500 1 4 Heavy damage. o 250 4 9 Slight damage. Do 100 9 15 No damage. Non-treated 30 36 Do.

Compound A is S-(2-chlorobenzyl)-N,N-di-iisopropylthiocarbamate, compound B is S-benzyi-N,N-di-isopropyl- I thiocarbamate as comparative compound.

EXPERIMENTAL EXAMPLE 2 Test method: A surface layer of paddy soil containing 7 seeds of the weed was fed in a Wagner pot of 1/5,000

are and stirred thoroughly therein. Then two groups of- 2 to 3 leafsta-ge paddy rice plant (species: Kinmaze), v,

each of which being composed of two paddy rice plants, were transplanted in the pot, on the next day a given amount of germinated barnyard grass seeds seeds per pot) was sowed thereon, and the pot was filled with water to a depth of 3 cm., and three days later a test solution obtained by diluting wettable powder of test compound shown in the following Table with 10 cc. of water, were dropped on the pot at a dose shown in the Table by means of a pipette. Twenty days after the treatment, the herbicidal activity and the phytotoxicity on paddy rice plant were determined.

Dose B ard B a1 1 Phytotigmity' arny roa ea on a Activeingredient g./10 a. grass Wlrograss weeds rice plan t Cl 5 4 3 isoCQ '1') 200 5 4.5 3

400 5 4.5 /N-S CH, isoC;H

isoCsH1 0 100 4.6 3 0 g 200 5 4 0 /N S-CH; 400 5 4.5 2 +to++ isoC;H

(Comparative compound) Cl 100 5 4.5 3 (3211\ 0 g 5 4.5 1+

g CH v 5 5 (71H;

(Comparative compound) 01 100 0 0 isoCQ 0 200 2 0 g 4 g OH I 00 3 3 2 d: isoO;H

(Comparative compound) Cl 1 C131 o 283 2 i i 400 4 4 3 m (Comparatlvefoompound) grass seeds per pot were TABLES-Continued Broadlaa! weeds Dose, Barnyard 5/10 a. grass Active ingredient Wlregrass N C- S --O H on paddy rice plant (Comparative compound) H I 1.100

NOD

C-SCHaisgCiHi U.B.P.2992091).:

TABLE-Continued .l:'.:.

' Phytotoxiclty a =-on paddy Active ingredient .110 v 5; i-rice plant I 1 CH 8 Cl M z a. 7 i 4 o 1 V i n.- ,1

K H 4 0 .a I I I /NCSCH2- C1 15001111 may. 2992091) 01 MW raga no"; raw 7 15001111 8 0 0. 400; 0- 0.- NC-SCHa- -Cl 1,.

isoCrHr (U.S.P. 2992091) 01 e-- -e--.-- .'.100 r .m sire-fink: -e'- tsoCaHv S 0; 0

.400 0: 0 nc-s CH -O. 1V :1 H,

isoCiHr (U.S.P. 2992091) c1 c1 400-: o o; iSOCaHI B 200.2 (I 0 1 400; o. o. NG-S CH Cl lsoCzHr V (U.S.P. 2992091) (Comparative compound, NIP) (Comparative compound, PCP-Na) N om:

0-; 100% growth (the same effect as in non-treated area).

5=nogrowth(completewitherlng). :11

;=)no damage.

+++=maximum damage (complete withering). [4 V What is claimed is References Cited a 1. A metiiod for killing grassy and broad leaf :weeds in 59 UNITED STATES PATENTS areas containing such weeds and rice plants which comprises applying to such areas and contacting s ai d g rassy v. z.v 1, 4 EFEF 'T' and broad leaf weeds and said rice plants with a phyto- 3,581,314 7197f -90 ct 7 7 p toxic amount with respect to said weeds and'ndn-injurioiis a r amount with respect to said rice plants of a composition 55 FOREIGN TE T comprising as an active herbicidal ingredient, S-(2-ch1oro- 995,497 6/1965 Great Britain 71- 100 benzyl)-N,N-di-isopropylthiocarbamate and an inert v a a diluent. 1 W... a...aJAMESHQVIHOMAS,Jaa nmaryvE amm r.a 

